Is My Child Obese How Can I Tell If Someone Else Is Using My Computer At Work?

How can I tell if someone else is using my computer at work? - is my child obese

I have reason to believe that others with my computer at work, but I do not know how to tell the insurance company. The reason why I believe that others are using the computer, because things move in my office all the time and broken. I know I have very few rights because I am an intern, but want to know if there a way for me to know whether other people use my computer while I'm gone!